US8992421B2

US8992421B2 - Highly articulated robotic probes and methods of production and use of such probes

Info

Publication number: US8992421B2
Application number: US13/880,525
Authority: US
Inventors: Joseph A. Stand; Robert A. DiDomenico; Brett Zubiate; Ian J. Darisse; J. Christopher Flaherty
Original assignee: Medrobotics Corp
Current assignee: Medrobotics Corp
Priority date: 2010-10-22
Filing date: 2011-10-21
Publication date: 2015-03-31
Anticipated expiration: 2031-10-21
Also published as: JP5711380B2; EP2629655A4; CA2815396A1; AU2016208441A1; EP2629655B1; AU2011316849A1; US10238460B2; JP2014500152A; JP5864002B2; US20190307521A1; US20140005683A1; AU2011316849B2; WO2012054829A2; US20150313449A1; JP2015120034A; EP2629655A2; WO2012054829A3

Abstract

A highly articulated robotic probe comprises an outer sleeve and an inner core. The outer sleeve and inner core include a plurality of links. The links of the outer sleeve and inner core are configured to pivot relative to one another. Various characteristics of the links determine the overall pivot angle of the articulated probe. Each of the plurality of links may have one or more channels. The channels form a semi-continuous passage from link to link and are configured to receive an elongated member such as an inner core, tool or cable. One or more cables may be used to control the outer links of the outer sleeve and the inner links of the inner core. Various characteristics of the cables determine the overall performance of the articulated probe.

Description

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/406,032, filed Oct. 22, 2010, the content of which is incorporated herein by reference in its entirety.

This application claims the benefit of U.S. Provisional Application No. 61/534,032, filed Sep. 13, 2011, the content of which is incorporated herein by reference in its entirety.

This application claims the benefit of U.S. Provisional Application No. 61/412,733, filed Nov. 11, 2010, the content of which is incorporated herein by reference in its entirety.

This application claims the benefit of U.S. Provisional Application No. 61/472,344, filed Apr. 6, 2011, the content of which is incorporated herein by reference in its entirety.

This application claims the benefit of U.S. Provisional Application No. 61/492,578, filed Jun. 2, 2011, the content of which is incorporated herein by reference in its entirety.

This application is related to U.S. Provisional Application No. 61/368,257, filed Jul. 28, 2010, the content of which is incorporated herein by reference in its entirety.

This application is related to PCT Application No PCT/US2011/044811, filed Jul. 21, 2011, the content of which is incorporated herein by reference in its entirety.

This application is related to U.S. patent application Ser. No. 11/630,279, filed Dec. 20, 2006, published as U.S. Patent Application Publication No. 2009/0171151, the content of which is incorporated herein by reference in its entirety.

FIELD

Embodiments relate generally to the field of robotics and, more particularly, to three dimensional, flexible, steerable robotic devices.

BACKGROUND

There are numerous types of steerable multi-linked probes, and such devices are utilized in a variety of different applications. Robert Sturges' U.S. Pat. No. 5,759,151, which is hereby incorporated by reference in its entirety, discloses a flexible, steerable device for conducting exploratory procedures. The device includes at least one spine, each having stiffening means for selectively rendering the spine rigid and flexible along its length. A flexible sheath surrounds the spine and is axially slidably moveable relative to the spine so that the sheath will follow and conform to the shape of a spine in the rigid state and resist further flexure when the spine is in a relaxed state. A steerable distal tip is provided on the distal end of the device. Controls for the distal tip are mounted on the proximal end of the device. Mechanisms are provided on the distal end of the device for selectively activating and deactivating the stiffening means of the spine. An instrument conduit may be mounted on the sheath. Howard Choset's U.S. patent application Ser. No. 11/630,279, which is hereby incorporated by reference in its entirety, discloses a feeder mechanism for advancing and retracting both an inner core and an outer sleeve, as well as selectively applying tension to control cables used for steering and causing either the inner core or outer sleeve to transition between a rigid state and a limp state.

U.S. Pat. No. 6,610,007, incorporated herein by reference, discloses a steerable endoscope having an elongated body with a selectively steerable distal portion and an automatically controlled proximal portion. The endoscope body is inserted into a patient and the selectively steerable distal portion is used to select a desired path within the patient's body. When the endoscope body is advanced, an electronic motion controller operates the automatically controlled proximal portion to assume the selected curve of the selectively steerable distal portion. Another desired path is selected with the selectively steerable distal portion and the endoscope body is advanced again. As the endoscope body is further advanced, the selected curves propagate proximally along the endoscope body, and when the endoscope body is withdrawn proximally, the selected curves propagate distally along the endoscope body. This creates a serpentine motion in the endoscope body allowing it to negotiate tortuous curves along a desired path through or around and between organs within the body.

For medical use and other critical applications, it is extremely important that each device not only perform as intended and within known specifications, but have repeatable performance and otherwise consistent operation from use to use. For these and other reasons, there is a need for improved systems, devices, and methods.

SUMMARY

According to one embodiment, an articulated probe having at least a portion configured to be controllably rigid and flexible, includes an inner core having a plurality of inner links; an inner cable extending through the plurality of inner links and configured to control the inner core; an outer sleeve having a plurality of outer links; and a plurality of outer cables extending through the plurality of outer links and configured to control the outer sleeve, wherein the inner cable has a tensile strength greater than each of the individual outer cables.

In some embodiments, the tensile strength of the inner cable is approximately equal to a combined tensile strength of the plurality of outer cables.

In some embodiments, each of the plurality of outer cables has approximately the same tensile strength.

In some embodiments, the tensile strength of each of the plurality of outer cables is approximately 1/Nth of a tensile strength of the inner cable, where N is the number of outer cables.

In some embodiments, each of the plurality of outer cables has approximately the same cross-sectional area.

In some embodiments, the cross-sectional area of each of the plurality of outer cables is approximately 1/Nth of a cross-sectional area of the inner cable, where N is the number of outer cables.

In some embodiments, the inner cable and the plurality of outer cables are comprised of at least one of steel, polyethylene, nylon and fluorocarbons.

According to another embodiment, an articulated probe includes a plurality of links configured to pivot relative to one another through a maximum pivot angle; and an elongated member, wherein at least two of the plurality of links includes a channel for receiving the elongated member therein, and wherein the channel in each of the plurality of links is tapered in an amount sufficient to permit the plurality of links to pivot through the maximum pivot angle while providing a substantially continuous surface between the channels of the links for the elongated member.

In some embodiments, the articulated probe comprises an inner core comprising a plurality of inner links, and wherein the channel is positioned within at least two of the plurality of inner links.

In some embodiments, the articulated probe comprises an outer sleeve comprising a plurality of outer links, and wherein the channel is positioned within at least two of the plurality of outer links.

In some embodiments, the articulated probe comprises an outer sleeve comprising a plurality of outer links; an inner core comprising a plurality of inner links; wherein the channel is positioned between at least two of the plurality of outer links and at least two of the plurality of inner links.

In some embodiments, the at least two of the plurality of links comprises a side port and the channel is positioned within the side port.

In some embodiments, the channel comprises a recess in the at least two of the plurality of links.

In some embodiments, the taper is approximately twice the maximum pivot angle.

In some embodiments, the taper is approximately 26 degrees and the maximum pivot angle is approximately 13 degrees.

In some embodiments, a diameter of the elongated member is less than a diameter of the channels of the links.

In some embodiments, the elongated member includes at least one of a tool and a cable.

In some embodiments, the elongated member includes an inner core formed of a plurality of inner links.

According to yet another embodiment, an articulated probe with a probe central axis includes an inner core having a plurality of inner links configured to pivot relative to one another and the probe central axis through an inner maximum pivot angle; and an outer sleeve having a plurality of outer links configured to pivot relative to one another and the probe central axis through an outer maximum pivot angle, and wherein the inner maximum pivot angle is no less than the outer maximum pivot angle.

In some embodiments, the plurality of outer links in the outer sleeve includes: a first outer link with a first central axis that can align with the probe central axis, the first outer link including an outwardly extending first flange with a first engagement surface extending radically outward relative to the first central axis; and a second outer link with a second central axis that can align with the probe central axis, the second outer link including an outwardly extending second flange with a second engagement surface extending radically outward relative to the second central axis, wherein the first outer link and second outer link are configured to permit the first and second outer links to pivot relative to one another and the probe central axis through the outer maximum pivot angle until the first engagement surface engages the second engagement surface.

In some embodiments, the first engagement surface tapers relative to a line perpendicular to the first central axis.

In some embodiments, the second engagement surface tapers relative to a line perpendicular to the second central axis.

In some embodiments, the first engagement surface tapers approximately 6.5° degrees and the second engagement surface tapers approximately 6.5° degrees.

In some embodiments, the outer maximum pivot angle is no greater than approximately 13 degrees.

In some embodiments, at least one of the plurality of inner links and the plurality of outer links includes channels configured to receive an elongated member therein, wherein the channels are tapered in an amount sufficient to permit pivoting through the outer maximum pivot angle while providing a substantially continuous surface between the channels for the elongated member.

According to another embodiment, an articulated probe, includes a plurality of links configured to pivot relative to one another, wherein the plurality of links includes a first link having a first concave portion and a first convex portion; a second link have a second concave portion and second convex portion, wherein the first convex portion of the first link pivotally engages the second concave portion of the second link, and wherein the first convex portion has a radius of curvature no greater than a radius of curvature of the second concave portion.

In some embodiments, each of the plurality of links has a concave portion and a convex portion that engage corresponding convex and concave portions of adjacent links, and the convex portions each have a radius of curvature no greater than a radius of curvature of the corresponding concave portion.

In another embodiment, a method of performing a surgical procedure comprises: selecting the articulated probe as described in any of the embodiments herein; and manipulating the probe to position at least one tool.

In another embodiment, a method of producing a link for an articulated probe formed of a plurality of links includes the steps of molding the link in molding device, including forming at least one engagement surface configured to engage an adjacent link in the articulated probe; ejecting the link from the molding device by pressing at least one ejection pin against an ejection surface of the link that will not engage an adjacent link in the articulated probe.

In some embodiments, the ejection surface is located in a recess in the link.

In another aspect, embodiments are directed to an articulated probe as described in reference to the figures.

In another aspect, embodiments are directed to a method of performing a medical procedure as described in reference to the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of embodiments of the present inventive concepts will be apparent from the more particular description of embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same elements throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments.

FIGS. 1A-1C are graphic demonstrations of a highly articulated probe device, in accordance with the present inventive concepts;

FIGS. 2A-2B illustrate various configurations assumed by a highly articulated probe, in accordance with the present inventive concepts;

FIGS. 3A-3D illustrate various views of a link of an outer sleeve, in accordance with the present inventive concepts;

FIGS. 4A and 4B illustrate end and cross-sectional views, respectively, of a link of an inner core, in accordance with the present inventive concepts;

FIGS. 5A and 5B illustrates one example of a feeder mechanism, in accordance with the present inventive concepts;

FIG. 6 illustrates devices for controlling the tension on cables, in accordance with the present inventive concepts;

FIG. 7 illustrates devices for controlling the tension on the cables of the outer sleeve, consistent with the present invention;

FIG. 8 illustrates a device for controlling the tension on the cable of the inner sleeve, in accordance with the present inventive concepts;

FIG. 9 is a block diagram illustrating the components of a control system and the flow of information between those components, in accordance with the present inventive concepts;

FIGS. 10A and 10B illustrate a cross section of an articulated probe according to an embodiment, in accordance with the present inventive concepts.

FIGS. 11A and 11B illustrate a cross section of an articulated probe according to an embodiment, in accordance with the present inventive concepts.

FIGS. 12A-12B illustrate a cross section of an outer sleeve according to an embodiment, in accordance with the present inventive concepts.

FIGS. 13A-13B illustrate a cross section of an inner core according to an embodiment, in accordance with the present inventive concepts.

FIG. 13C illustrates a view of an inner link having an inner cable positioned in an outer link having a plurality of outer cables according to an embodiment.

FIGS. 14A-14I illustrate various views of an outer link, according to an embodiment, in accordance with the present inventive concepts.

FIGS. 15A-15J illustrate various views of an outer link transition segment, according to an embodiment, in accordance with the present inventive concepts.

FIGS. 16A-16K illustrate various views of an outer link with tool side ports, according to an embodiment, in accordance with the present inventive concepts.

FIGS. 17A-17I illustrate various views of an inner link, according to an embodiment, in accordance with the present inventive concepts.

FIG. 18 is a flow chart for producing a link for an articulated probe according to an embodiment, in accordance with the present inventive concepts.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings. This inventive concepts may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Like numbers refer to like elements throughout the specification.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various limitations, elements, components, regions, layers and/or sections, these limitations, elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one limitation, element, component, region, layer or section from another limitation, element, component, region, layer or section. Thus, a first limitation, element, component, region, layer or section discussed below could be termed a second limitation, element, component, region, layer or section, and vice-versa, without departing from the teachings of the present application.

It will be understood that when an element is referred to as being “on” or “connected” or “coupled” to another element, it can be directly on or connected or coupled to the other element or intervening elements can be present. In contrast, when an element is referred to as being “directly on” or “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). When an element is referred to herein as being “over” another element, it can be over or under the other element, and either directly coupled to the other element, or intervening elements may be present, or the elements may be spaced apart by a void or gap.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Overview of Highly Articulated Robotic Probe

A highly articulated robotic probe 10, according to one embodiment shown in FIGS. 1A-1C, is essentially two concentric mechanisms, an outer one and an inner one, each of which can be viewed as a steerable mechanism. FIGS. 1A-1C show the concept of how different embodiments of the probe 10 operate. Referring to FIG. 1A, the inner mechanism is referred to as a first mechanism, an inner core or inner core mechanism 12. The outer mechanism is referred to as a second mechanism, an outer sleeve or outer sleeve mechanism 14. Each mechanism can alternate between being rigid and limp. In the rigid mode or state, the mechanism is just that—rigid. In the limp mode or state, the mechanism is highly flexible and thus either assumes the shape of its surroundings or can be reshaped. It should be noted that the term “limp” as used herein does not denote a structure that passively assumes a particular configuration dependent upon gravity and the shape of its environment; rather, the “limp” structures described in this application are capable of assuming positions and configurations that are desired by the operator of the device, and therefore are articulated and controlled rather than flaccid and passive.

With this probe 10, one mechanism starts limp and the other starts rigid. For the sake of explanation, assume the outer sleeve 14 is rigid and the inner core 12 is limp, as seen in step 1 in FIG. 1A. Now, the inner core 12 is both pushed forward by a feeding mechanism 16, described below, and its “head” or distal end is steered, as seen in step 2 in FIG. 1A. Now, the inner core 12 is made rigid and the outer sleeve 14 is made limp. The outer sleeve 14 is then pushed forward until it catches up or is coextensive with the inner core 12, as seen in step 3 in FIG. 1A. Now, the outer sleeve 14 is made rigid, the inner core 12 limp, and the procedure then repeats. One variation of this approach is to have the outer sleeve 14 be steerable as well. The operation of such a device is illustrated in FIG. 1B. In FIG. 1B it is seen that each mechanism is capable of catching up to the other and then advancing one link beyond. According to one embodiment, the outer sleeve 14 is steerable and the inner core 12 is not. The operation of such a device is shown in FIG. 1C.

In medical applications, once the probe 10 arrives at a desired location, the operator, typically a surgeon, can slide one or more tools through one or more channels of outer sleeve 14, inner core 12, or a channel formed between outer sleeve 14 and inner core 12, such as to perform various diagnostic and/or therapeutic procedures. In addition to clinical procedures such as surgery, probe 10 can be used in numerous applications including but not limited to: engine inspection, repair or retrofitting; tank inspection and repair; spying and surveillance applications; bomb disarming; inspection or repair in tightly confined spaces such as submarine compartments or nuclear weapons; structural inspections such as building inspections; hazardous waste remediation; biological sample recovery such as anthrax recovery; and combination of these. Clearly, the device of the present disclosure has a wide variety of applications and should not be taken as being limited to any particular application.

Inner core

12 and/or outer sleeve 14 are steerable and inner core 12 and outer sleeve 14 can each be made both rigid and limp, allowing probe 10 to drive anywhere in three-dimensions. Probe 10 can “remember” its previous configurations and for this reason, probe 10 can go anywhere in a three dimensional volume such as the intracavity spaces in the body of a patient such as a human patient. FIGS. 2A-2B illustrate examples of various configurations assumable by probe 10.

As can be seen in FIGS. 3A-3D and 4A and 4B, according to one embodiment, the outer sleeve 14 and inner core 12, respectively, can be made up of concentric cylinders,

links

22, 24, respectively, although links of other shapes may be used, e.g. a dog bone configuration (not shown) as well as links of a type that are not concentric, e.g. backbone configuration, among others. The ends of the

links

22, 24 are not flat but instead one end 26 is an “outer” or convex hemisphere and the other end 28 is an “inner” or concave hemisphere, both typically with similar radius of curvature. The links 22, or links, of the outer sleeve 14 are “chained” back-to-back such that the concave end 28 of one mates with the convex end 26 of an adjacent link. Similarly, the links 24, or links, of the inner core 12 are chained back-to-back. The result is a spherical-like joint, from a kinematic point of view. In the current embodiment, each link is able to rotate on the adjacent link's head, acting as a spherical joint with approximately 10-20 degrees range of motion in any direction, although other ranges of motion are possible and potentially advantageous. According to one embodiment, the links 22 have a plurality of channels 30 extending therethrough for control cables or elongate devices such as elongate tools.

The heads (i.e. the distal links) of either or both the outer sleeve 14 and the inner core 12 are steerable using three cables which are attached at, for example, 120° from each other. As can be seen in FIGS. 3A-3D, there are three small cylindrical channels 30, 32, respectively, for cables to pass through. In the version of the device shown in FIGS. 4A and 4B, the inner link 24 has only one cable, in which case there is only one hole 34 through its center.

It will be appreciated that although the embodiment described above utilizes cables such as conductive or non-conductive wires or other flexible filamentous structure, alternative means of manipulating the limp elements, such as miniature pneumatic or hydraulic pistons or other mechanical linkages situated between individual links, can be employed without falling outside the scope of the present inventive concepts.

The links, and hence probe 10, can be made out of virtually any material, including plastic or other magnetic resonance imaging compatible material. The outer sleeve 14 may assume a broad range of diameters, typically greater than 5 mm. Similarly, inner core 12 may assume a broad range of diameters, less than the diameter of outer sleeve 14 and typically more than 3 mm. The total number of links can vary over a large range but is typically greater than 10 links.

As noted, the inner core 12 and outer sleeve 14 can be made rigid or limp using cables or other flexible filament structures. In one embodiment, outer sleeve 14 consists of a set of links 22 strung on three cables. The three cables are typically 120 degrees apart, making it possible to steer in any direction. Radius of curvature of probe 10 is dependent on a number of factors including length of links 22 as well as mating dimensions between the ends of mating links 22. When the cables are pulled toward the back of the outer sleeve 14, the links 22 are pulled toward each other. When the pulling force increases, the friction force between adjacent links 22 increases until the entire outer sleeve 14 stiffens (i.e. enters the rigid mode). When the pulling force is released, the outer sleeve 14 becomes limp. Thus, the cables together with their respective tensioning assemblies (e.g. motor driven pullies) form a locking device. The tensioning assemblies, along with the electronics for controlling the tensioning assemblies, comprise a means for controlling the tension on the cable. When the outer sleeve 14 is positioned one link in front of the inner core 12, and the inner core 12 is stiff, the distal link of the outer sleeve 14 can be oriented by pulling one or more of the three cables. In addition to advancing or retracting cable, the magnitude of the pulling force which is exerted on each cable can be monitored or controlled. By pulling the three cables with the same magnitude, the outer sleeve 14 becomes stiff without changing its shape.

The inner core 12, like the outer sleeve 14, consists of a set of links. According to one embodiment, in contrast to the outer sleeve 14, the inner core 12 does not need (but may optionally have) a steering ability. The inner core 12 does need the ability to change from rigid mode, to limp mode, and back. Therefore, in embodiments where the inner core 12 need not be steerable, the links of the inner core 12 may be strung on a single cable, which enables a reduced overall diameter for probe 10.

Overview of Feeding Mechanism

As mentioned above, a feeding mechanism 16 can be used to control the probe 10. One type of feeding mechanism 16, shown in FIGS. 5A and 5B, inserts and retracts the probe 10 into and out of respectively, a region of interest such as the esophagus, the peritoneal space, the pericardial cavity, or another internal space of a patient. The feeder 16 has two movable carts. A first cart 42, carried in a first fixed tray 43, advances and retracts the outer sleeve 14 while a second cart 44, carried in a second fixed tray 45, advances and retracts the inner core 12. Each

cart

42, 44, and hence each of the inner core 12 and outer sleeve 14, is driven independently by separate

linear actuators

46, 48 respectively. The

linear actuators

46, 48 may carry shaft encoders (not shown) used for position control as is known. Alternatively or additionally, motor current may be monitored to determine a value for tension in a cable used to control position. Cable tension may be monitored with one or more sensors such as a load cell. Numerous positioning and other sensors may be included to provide information relative to cable tension; cart position; probe orientation and configuration; and other system parameters. Typical sensors include but are not limited to: optical sensors; magnetic sensors such as Hall effect sensors; force and pressure sensors such as accelerometers, strain gauges and mechanical switches; and combinations of these. One or more sensors may be positioned in multiple locations including but not limited to: feeding mechanism 16, inner core 12 and outer sleeve 14.

Each of the

carts

42, 44 carries one or more motors necessary for controlling the cables of the inner core 12 and outer sleeve 14. For example, as seen in FIG. 6 and FIG. 7, the cart 42 carries

motors

50, 51, 52 which control the tension on

cables

54, 55, 56 of outer sleeve 14. As shown in FIG. 8, second cart 44 has a motor 58 for controlling the tension on cable 59 of the inner core 12. Each of the

motors

50, 51, 52 and 58 may be provided with shaft encoders (not shown) used for position control as is known. In an embodiment where the inner core 12 is steerable, the inner core 12 requires two or more motors (e.g. to tension two or more cables) or another cable tensioning mechanism.

FIG. 9 is a block diagram illustrating the components of one embodiment of a control system and the flow of information between those components. The feeding mechanism 16 interfaces with a control computer 62 through a bus conversion module 64. Outgoing data from the feeding mechanism 16 is input to the module 64 for conversion to the USB and is then input to a USB port 66 on the computer 62. Incoming data to control software 68 may include motor current data, motor encoder data and/or cable tension data associated with each of the cables in the feeding mechanism 16. Alternatively or additionally, incoming data to control software 68 may include data from one or more sensors located in feeding mechanism 16, inner core 12 or outer sleeve 14. Joystick data (position data) may also be received from a joystick 70. A monitor 72 may be responsive to video data from a camera mounted on the distal end of the outer sleeve 14 and/or inner core 12 to provide visual feedback to a user regarding the position of the distal end of the probe 10. The control software 68 may output motor current limit commands and motor position commands which are input to the feeding mechanism 16.

Inner Core and Outer Sleeve

FIGS. 10A-11B illustrate an embodiment of the articulated probe 10 with the inner core 12 and the outer sleeve 14. The inner core 12 has a plurality of inner links 100 (preferably at least three, and, in some embodiments, fifty or more). The outer sleeve 14 has a plurality of outer links 104 (preferably at least three, and, in some embodiments, forty or more).

With regard to the outer links, FIGS. 14A-16J illustrate various views of presently preferred embodiments of such

outer links

104, 132. These embodiments of the outer links are similar to those discussed in the overview above. However, these embodiments differ in some significant aspects from those discussed above, as well as from each other. The present embodiments of the

outer links

104, 132 can be combined to form a unique outer sleeve 14, such as shown in FIG. 11A. In particular, FIGS. 16A-16K illustrate various views of outer links 104 with tool side ports 128. The tool side ports 128 can be used to receive and guide tools. FIGS. 15A-15J illustrate various views of transition outer links 132. As shown in FIG. 11A, a plurality of transition outer links 132 can be positioned adjacent an outer link 104 with tool side ports 128. The transition outer link 132 can have one or more recesses 130 that accommodates and funnels elongated members, such as tools, into the tool side port 128 of the outer link 104. For example, the inner diameter of the

outer link

104, 132 preferably is in the range of 0.10-2.00 inches, and more preferably the inner diameter, is approximately 0.394 inches. The outer diameter of the

outer link

104, 132 preferably is in the range of 0.20-3.00 inches, and more preferably the outer diameter is approximately 0.669 inches. The

outer link

104, 132 may be comprised, for example, of at least one of metals, plastics, glass, carbon fiber, etc. In a particular embodiment, the

outer link

104, 132 is comprised, for example, of polyphenylsulfone (e.g., Radel® R-5100).

With regard to the inner links 100, FIGS. 17A-17I illustrate various views of presently preferred embodiments. These inner links 100 are similar to those discussed in the overview above. However, they differ in some significant aspects. The length of the inner link 100 preferably is in the range of 0.01-2.00 inches, and more preferably the length of the inner link 100 is 0.353 inches. The outer diameter of the inner link preferably is in the range of 0.10-2.00 inches, and more preferably, the inner diameter is 0.354 inches. The inner link 100 may be comprised, for example, of at least one of metals, plastics, glass, carbon fiber, etc. In a particular embodiment, the inner link 100 is comprised of plastic with embedded glass fiber (30% by weight).

The inner links 100 are configured to pivot relative to one another through a maximum pivot angle, and the outer links 104 are configured to pivot relative to one another through a maximum pivot angle, as shown for example in FIGS. 10A-13B. Preferably, the maximum pivot angle of the inner links 100 is no less than the maximum pivot angle of the outer links 104. In view of this pivoting relationship, it can be important for the

links

100, 104 to be configured in such a way to avoid one or more undesired conditions such as: limiting the articulated probe 10 flexion; pinching of an elongated member that may be positioned within the

links

100, 104; and problems that might occur with the advancement and retraction of the elongated member.

Each of the plurality of inner links 100 and/or outer links 104 may have one or more channels 108 for receiving an elongated member. Alternatively or additionally, mating recesses in inner links 100 and outer links 104 may create one or more channels between inner core 12 and outer sleeve 14. An elongated member may be any one of a tool, an inner cable 102, an outer cable 106, or an inner core 12. Typical elongate tools include but are not limited to: scissors, scalpels and other cutting tools; graspers such as tissue graspers; energy delivery elements such as tissue ablation elements, electrocautery and coagulation elements; cambers such as fiber optic cameras; heating elements; cooling elements; drug delivery devices; and combinations of these. As discussed in the overview, the tool can be used to perform various operations and one or more cables may be used to control the outer links 104 of the outer sleeve 14 and the inner links 100 of the inner core 12. The channels 108 are configured to form a semi-continuous passage from

link

100, 104 to an

adjacent link

100, 104 and can include a liner to facilitate reception of the elongated member. As shown in FIG. 14G, the channel 108 may have a circumferential flare. The circumferential flare avoids pinching elongated members within the channel 108 and facilitates rotation of the plurality of

links

100, 104 while significantly reducing any difficulty that may be encountered by advancing or retracting an elongated member through the probe 10. Further, the channels 108 of inner links 100 and/or outer links 104 may be tapered to achieve a semi-continuous passage from

link

100, 104 to link 100, 104.

According to one embodiment, the channel 108 in each of the inner links 100 and/or outer links 104 is tapered in an amount sufficient to permit the inner links 100 and/or outer links 104 to pivot through the maximum pivot angle while providing a substantially continuous surface between the channels 108 of the

links

100, 104 for receiving the elongated member. More preferably, the opening and/or exit of the channel 108 can be tapered. The tapered openings and exits of the channel 108 avoid pinching elongated members within the channel 108 and significantly reduce any difficulty that may be encountered by advancing or retracting an elongated member through the probe 10. In addition, the tapered openings correlate to the radius of curvature of probe 10. According to one embodiment, the taper of the channel 108 is approximately twice the maximum pivot angle. For example, the taper can be approximately 26° degrees and the maximum pivot angle can be approximately 13° degrees. The taper of the channel 108 preferably can accommodate a pivot angle of 13° degrees or greater. In sum, the tapered channels 108 are configured to provide a substantially continuous surface between the channels 108 of the

links

100, 104 for the reception of the elongated member.

The inner links 100 of the inner core 12 may have the channel 108 positioned near a central axis and configured to receive an inner cable 102 (the elongated member), as shown in FIGS. 13A-B and 17A-17I. The channel 108 within the inner links 100 can have a flared opening. According to one embodiment, the flared opening is positioned off-center in relation to the central axis of the inner link 100. Positioning the flared opening off-center allows the pivot point of the inner cable 102 to change more easily when the pivot point of the inner core 12 may change due to rotation of the inner core 12 or any other form of translational displacement that may occur. Preferably, the diameter of the channels 108 of the inner links 100 is greater than the diameter of the inner cable 102, which reduces the occurrence of twisting and sawtoothing of the inner links 100. For example, if the channel 108 preferably has a diameter in the range of 0.003-0.500 inches (more preferably approximately 0.043 inches), the diameter of the inner cable 102 preferably is in the range of 0.002-1.000 inches (more preferably approximately 0.037 inches). By configuring the diameter of the inner cable 102 and channel 108 of the inner links 100 to reduce twisting and sawtoothing, the likelihood of pinching or difficulty with advancement and retraction of the elongated member is also significantly reduced. Thus, the channel 108 of the inner link 100 provides a substantially continuous surface between links 100 for the inner cable 102.

The outer links 104 of the outer sleeve 14 also may have the channel 108 formed therein for the reception of an elongated member, as shown for example in FIG. 12A. In this particular embodiment, the elongated member can be an inner core 12 with a plurality of inner links 100. The channel 108 includes a plurality of outer links 104, each having a flared opening. As shown in FIG. 12A, the flared opening in each of the plurality of links 104 provide a substantially continuous surface between links 104 for reception of the inner core 12. The channels 108 of the outer links 104 are also tapered in an amount sufficient to permit an inner core 12 to pivot through a maximum pivot angle while providing a substantially continuous surface between the channels 108 for the inner core 12. The taper of the channels 108 also allows flexion of the inner links 100. Preferably, the inner flexion of the inner links 100 may be greater than or equal to 13° degrees. Thus, the channel 108 of the outer link 104 provides a substantially continuous surface between links 104 for the reception of the inner core 12.

A plurality of channels 108 also may be positioned near the outer surface of the outer link 104, as shown in FIGS. 14A-16K. According to one embodiment, three channels 108 are positioned approximately 120° degrees from each other around a circumference of one or more outer links 104 making up the outer sleeve 14. The channels 108 of the outer link 104 are configured to receive an elongated member in the form of outer cables 104 for controlling the outer sleeve 14. Preferably, a diameter of the outer cables 106 is less than a diameter of the channels 108 of the outer links 104, which reduces the occurrence of twisting and sawtoothing of the outer links 104. According one embodiment, the diameter of the outer cables 106 may be in the range of 0.002-1.000 inches. In one embodiment, the diameter of outer cables 106 is 0.027 inches. The diameter of the channels 108 in each outer link 104 for receiving the outer cables 106 may be in the range of 0.003-0.500 inches. In a particular embodiment, the diameter of the channels 108 in each outer link 104 are approximately 0.035 inches. By configuring the diameter of the outer cables 106 and channels 108 of the outer links 104 to reduce twisting and sawtoothing, the likelihood of pinching or difficulty with advancement and retraction of the elongated member is also significantly reduced. Thus, the channels 108 of the outer link 104 provides a substantially continuous surface between links 104 for the plurality of cables 106.

A combination of the inner link 100 and the outer link 104 also may be configured so as to provide the channel 108 for receiving an elongated member. With reference to FIGS. 14A-14I, an inner surface of the outer link 104 can have a flared indentation 134 which forms one half of a channel 108 for receiving an elongated member in the form of a tool. As shown in FIGS. 17A-17I the other half of the channel 108 is formed by flared indention 136 on the outer surface of the inner link 100. The channel 108 formed by the flared indention 136 of the inner link 100 and the flared indention 134 of the outer link 104 provides a substantially continuous surface between

links

100, 104 for one or more tools.

The

outer links

104 and 132 shown in FIGS. 15A-16K can both be configured to receive an elongated member in the form of a tool, cable, or other elongated device. With respect to FIGS. 11A and 16A-16K, the channels 108 of an outer link 104 can be formed by tool side ports 128. The tool side ports 128 extend out from the outer circumference of the outer link 104 and are configured with a channel 108 to receive tools, cables, or other elongated devices. As shown in FIG. 11A, the transition outer link 132 is positioned between an outer link 104 and an outer link 104 with tool side ports 128 along the length of the probe 10. According to one embodiment and as shown in FIGS. 15A-15J, the transition outer link 132 has one or more recesses 130 that accommodates and funnels tools into an outer link 104 having a tool side port 128. Accordingly, tools configured for use approximately outside the circumference of the probe 10 can be received by the channels 108 formed by the tool side ports 128 and the recesses 130 of the transition outer link 132. The channels 108 formed by the tool side ports 128 and the recesses 130 provides a substantially continuous surface between the

outer links

104, 132 for one or more elongate devices.

The radius of curvature of the articulated probe 10 can depend on the pivot angle of the inner and

outer links

100, 104. With respect to FIGS. 10A-12B and 14A-I, the outer sleeve 14 may include a plurality of outer links 104 having an outwardly extending flange 110. The flange 110 is configured to control the pivot angle of the outer links 104 relative to one another. Thus, characteristics of the flange 110 impact the radius of curvature of the articulated probe 10 that can be achieved.

According to one embodiment, the geometry of the flange 110 determines the degree of pivot possible between each of the outer links 104. With respect to FIGS. 14D-14E, the flange 110 can have a first engagement surface 112 and a second engagement surface 114 extending radially outward relative to a first central axis of the outer link 104. The flange 110 is configured to permit the outer links 104 to pivot relative to one another and a probe central axis through an outer maximum pivot angle until the first engagement surface 112 of a first outer link 104 and the second engagement surface 114 of a second outer link contact each other. According to one embodiment, the first engagement surface 112 and the second engagement surface 114 taper relative to a line perpendicular to a central axis of the outer link 104. With reference to FIG. 14E, in one particular embodiment, the first engagement surface 112 tapers approximately 6.5° degrees and the second engagement surface 114 tapers approximately 6.5° degrees. According to this embodiment, the outer maximum pivot angle is no greater than approximately 13° degrees. In alternative embodiments, the taper of the first engagement surface 112 and the second engagement surface 114 may be configured so that the maximum pivot angle is greater that 13° degrees, or less than 13 degrees. Preferably, the geometry of the flange 110 is configured so that the radius of curvature of the articulated probe 10 is in the range of 10-600 mm. Thus, the geometry of the flange 110 can be used to set the maximum pivot angle of the outer links 104, which in turn impacts a range of the radius of curvature of the articulated probe 10.

The

links

100, 104, 132 can be configured to reduce the occurrence of irregular or undesired forces (e.g. irregular or undesired frictional engagement forces) acting between a first and

second link

100, 104. For example, as shown in FIGS. 14B, 14H, 15B, 15C, 15I, 16B, 16C, 16J, 17C, 17D, 17H, the plurality of inner links 100 and outer links 104 may include a first concave portion 120 and a first convex portion 122. A convex portion 122 of a

first link

100, 104 can pivotally engage a corresponding concave portion 120 of a

second link

100, 104. According to a particular embodiment, the

first link

100, 104

convex portion

122 has a radius of curvature no greater than a radius of curvature of the

second link

100, 104

concave portion

120. The

links

100, 104 can be linked together to form an inner core 12 and outer sleeve 14. The arrangement of the links 100, 104 (a concave portion 120 pivotally engaging a corresponding convex portion 122) allows the inner core 12 and outer sleeve 14 to pivot with a wide range of motion and reduces the occurrence of irregular or undesired frictional or other forces between

links

100, 104 that may interfere with efficient operation of the articulated probe 10.

As demonstrated above, the physical characteristics of the various features of the inner core 12 and outer sleeve 14 affect the properties and performance of the articulated probe 10 in various ways. According to one embodiment, the geometric dimensions of one or more channels of an outer link 104 are mathematically related to one or more parameters of outer link 104. These parameters may include: the radius of an end of outer link 104; the diameter of outer link 104; the pivot angle between outer links 104; diameter of the channel such as average diameter of the channel; the channel location such as the distance of the channel from a central axis of outer link 104.

It can be advantageous to form the links in a way that facilitates smooth articulation of one link relative to the other and avoids undesired mating forces such as irregular frictional engagement between adjacent links. With respect to FIGS. 17A, 17B, 17D-17F, 17I and 18 a method for producing a

link

100, 104 for an articulated probe 10 will now be described. In step 210, the

link

100, 104 is molded in a molding device, including forming at least one engagement surface configured to engage an

adjacent link

100, 104 in the articulated probe 10. In step 212, the

link

100, 104 is ejected from the molding device by pressing at least one ejection pin 124 (see FIG. 17E) against an ejection surface 126 of the

link

100, 104 that will not engage an

adjacent link

100, 104 in the articulated probe 10. As shown in FIGS. 17A, 17B, 17D-E and 17I, according to one embodiment, the ejection surface 126 is located in a recess in the

link

100, 104. Strategically positioning the ejection surface 126 on a

link

100, 104 ensures that the ejection surface 126 does not affect the interaction of one

link

100, 104 with another such as by positioning any ejection pin imperfections away from the mating surfaces between adjacent links. Thus, the above-described procedure ensures that each

link

100, 104 articulates smoothly relative to another

link

100, 104.

Cables

As discussed in the overview above, one or more cables may be used to control the outer links 104 of the outer sleeve 14 and the inner links 100 of the inner core 12. Further examples of cable configurations are described below. In these configurations, as shown in FIG. 12B, a plurality of outer cables 106 can extend through the plurality of outer links 104. The outer cables 106 are configured to control (e.g. steer and transition between flexible and rigid) the outer sleeve 14. In an embodiment, each of the plurality of outer cables 106 has approximately the same tensile strength and/or approximately the same cross-sectional area.

As shown in FIGS. 13A-13B, an inner cable 102 extends through the plurality of inner links 100. The inner cable 102 is configured to control inner core 12 (e.g. transition between flexible and rigid). In an embodiment, the tensile strength and/or cross sectional area of the inner cable 102 is related to the tensile strength and/or cross sectional area of the plurality of outer cables 106.

The relationship between the tensile strength and/or cross sectional area of the inner cable 102 and the plurality of outer cables 106 provide for efficient movement and operation of the articulated probe 10. With regard to tensile strength, the inner cable 102 can have a tensile strength greater than each of the individual outer cables 106. In some embodiments, the tensile strength of the inner cable 102 is approximately equal to a combined tensile strength of the plurality of outer cables 106. In some embodiments, the tensile strength of each of the plurality of outer cables 106 is approximately 1/Nth of a tensile strength of the inner cable 102, where N is the number of outer cables 106. For example, the tensile strength of the inner cable 102 and the combined tensile strength of the outer cables 106 can be in the range of 2-500 lbs, and, in some embodiments, is about 30 lbs.

With regard to cross-sectional area, as shown in FIG. 13C, the cross-sectional area (A_o) of each of plurality of outer cables 106 can be as small as approximately 1/Nth of a cross-sectional area (A_i) of the inner cable 102, where N is the number of outer cables. This relationship is particularly, though not exclusively, important in a configuration where the

cables

102, 106 are formed of the same material and/or when the probe 10 diameter is minimized.

The material forming the inner and

outer cables

102, 106 can impact the configuration of the cables. The inner cable 102 and the plurality of outer cables 106 may be comprised of the same material, which, in some embodiments, can be at least one of steel, polyethylene (UHMW-ultra-high-molecular-weight), plastic, nylon and fluorocarbons, with steel being more preferred in some embodiments. The inner cable 102 and the plurality of outer cables 106 can be formed from by a monofilament or braided technique. However, the desired tensile strength relationships can also be achieved by using different materials for the inner cable 102 and the outer cables 106.

In sum, the inner cables 102 and outer cables 106 used to control the inner core 12 and outer sleeve 14 can have various characteristics. These characteristics include, but are not limited to the tensile strength, the cross-sectional area and the composition of the

cables

102, 106. Configuring the cables based on desired characteristics and relationships with respect to the inner cable 102 and the outer cables 106 determine the stability and other performance parameters of the articulated probe 10.

While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventive concepts. Modification or combinations of the above-described assemblies, other embodiments, configurations, and methods for carrying out the invention, and variations of aspects of the inventive concepts that are obvious to those of skill in the art are intended to be within the scope of the claims. In addition, where this application has listed the steps of a method or procedure in a specific order, it may be possible, or even expedient in certain circumstances, to change the order in which some steps are performed, and it is intended that the particular steps of the method or procedure claim set forth here below not be construed as being order-specific unless such order specificity is expressly stated in the claim.

Claims

We claim:

1. An articulated probe having at least a portion configured to be controllably rigid and flexible, comprising:

an inner core having a plurality of inner links;

an inner cable extending through the plurality of inner links and configured to control the inner core;

an outer sleeve having a plurality of outer links; and

a plurality of outer cables extending through the plurality of outer links and configured to control the outer sleeve,

wherein the inner cable extending through the inner links of the inner core has a tensile strength that is greater than that of each of the individual outer cables extending through the outer links.

2. The articulated probe of claim 1, wherein the tensile strength of the inner cable is approximately equal to a combined tensile strength of the plurality of outer cables.

3. The articulated probe of claim 1, wherein each of the plurality of outer cables has approximately the same tensile strength.

4. The articulated probe of claim 3, wherein the tensile strength of each of the plurality of outer cables is approximately 1/Nth of a tensile strength of the inner cable, where N is the number of outer cables.

5. The articulated probe of claim 1, wherein each of the plurality of outer cables has approximately the same cross-sectional area.

6. The articulated probe of claim 5, wherein the cross-sectional area of each of the plurality of outer cables is approximately 1/Nth of a cross-sectional area of the inner cable, where N is the number of outer cables.

7. The articulated probe of claim 1, wherein the inner cable and the plurality of outer cables are comprised of at least one of steel, polyethylene, nylon and fluorocarbons.

8. The articulated probe of claim 1, wherein the tensile strength of each of the outer cables is less than or equal to the tensile strength of the inner cable and greater than or equal to 1/Nth of the tensile strength of the inner cable, where N is the number of outer cables.

9. The articulated probe of claim 1, wherein the inner cable has a diameter that is greater than those of each of the individual outer cables.